During an infection with Plasmodium falciparum, the 92 kDa knob protein (KP) and a 102 kDa protein are known to alter the erythrocyte either by association with or insertion into the membrane. The main objectives of the present proposal are to study the structure and expression of these two erythrocyte membrane-associated P. falciparum-encoded proteins. The approach will be initially to construct cDNA libraries in pUC9 or Lambdagt11 using poly(A)+ RNA derived from infected erythrocytes at appropriate stages of the life cycle. Subsequently, the libraries will be screened for the expression of these proteins using monoclonal and polyclonal antibodies. Positive cDNA clones will be used to isolate the entire gene froma P. falciparum genomic library. The nucleotide sequence of the genes will be determined and, using these data, subclones will be constructed containing the entire gene in various high expression vectors. Using such systems, large quantities of proteins will be synthesized, purified, andused to immunize rabbits to produce highly specific, high affinity antisera. These antisera will be used to study the biosynthesis of these parasite proteins and their association with the erythrocyte membrane. The application of molecular biological techniques to study the biosynthesis of these proteins may elucidate a mechanism essential to parasite survival in the host, which may lead to new therapeutic approaches to malaria.